1. Field of the Invention
This invention relates to a steering unit-mounting structure for mounting a steering unit (switch box), having combination switches (provided in the vicinity of a steering wheel of an automobile) for turning signal lamps, wipers, headlights and so on, on a steering post.
2. Description of the Related Art
FIG. 5 shows a steering wheel mounting portion of an ordinary construction in an automobile. A steering shaft 10 is rotatably supported on a steering post 20. A steering unit 30 and a rotary connector (rotary connection device) 40 are mounted on that portion of the steering post 20 disposed in a car room. A steering wheel 50 is mounted on a distal end portion 11 of the steering shaft 10, extending through the steering unit 30 and the rotary connector 40, so as to rotate with the steering shaft 10. An electric equipment 51, such as a horn switch and an air bag, is mounted on the steering wheel 50. Combination switches for turning signal lamps, wipers and so on, are incorporated in the steering unit 30, and operating levers 31 and 32 for effecting the switching operation of these switches are mounted on left and right side surfaces of the steering unit 30, respectively. A wire harness 60 for connecting a control circuit on a vehicle body to the electric equipment 51 on the steering wheel 50 and the combination switches in the steering unit 30 is arranged to extend along the steering post 10, and for example, female connectors 61 are fixedly secured to a distal end of this wire harness.
FIG. 6 shows a conventional mounting structure for mounting the steering unit 30 on the steering post 10. The distal end of the wire harness 60 projects slightly beyond a distal end 21 of the steering post 20. The distal end of the wire harness 60 is divided into a plurality of sections, and the female connectors 61a to 61c are fixedly secured to these sections, respectively. A recess 22 for receiving the projected portion of the wire harness 60 after the connection of the connectors is formed in the steering post 20 in adjacent relation to a distal end 21 thereof. A through hole 33 for fitting on the steering shaft 10, projecting from the steering post 20, is formed through the steering unit 30, and male connectors 62a to 62c for connection respectively to the female connectors 61a to 61c are fixedly mounted on the steering unit 30.
Generally, in connectors, male terminals are press-fitted respectively into female terminals, thereby making an electrical connection therebetween. Therefore, the number of pins in the connector, which can be manually connected, is limited. Therefore, as shown in FIG. 6, the distal end of the wire harness is divided into a plurality of sections, and the connection must be made using the plurality of connectors 61a to 61c and 62a to 62c. 
For mounting the steering unit 30 on the steering post 20, the operator first holds the steering unit 30 with one hand, and in this condition the male connectors 62a to 62c are connected to the female connectors 61a to 61c, respectively. Then, that portion of the wire harness 60, projecting from the distal end 21 of the steering post 20, and the female connectors 61a to 61c are pushed into the recess 22 in the steering post 20, and in this condition the steering shaft 10 is passed through the through hole 33 in the steering unit 30. Then, the steering unit 30 and the steering post 20 are positioned relative to each other, and thereafter the steering unit 30 is fixed to the steering post 20 by bolts or the like (not shown).
In the above conventional steering unit-mounting structure, however, the female connectors 61a to 61c, associated with the steering post 20, must be manually connected respectively to the male connectors 62a to 62c on the steering unit 30, and this operation must be carried out in the narrow cockpit of the automobile, and therefore the mounting operation is very difficult. In FIG. 6, although the wire harness 60 and the connectors 61a to 61c and 62a to 62c are arranged on one side of the steering shaft 10, such wire harness 60 and connectors 61a to 61c and 62a to 62c must be arranged on each side of the steering shaft 10 if the number of circuits increases. In this case, the number of the connectors increases, which leads to high possibilities of a connection error, a connection omission and incomplete connection.
And besides, the plurality of connectors 61a to 61c must be connected respectively to the plurality of connectors 62a to 62c while holding the steering unit 30 with one hand, and therefore the efficiency of the operation is low. Furthermore, when pushing that portion of the wire harness 60, projecting from the distal end 21 of the steering post 20, into the recess 21 in the steering post 20, the elasticity of the wire harness provides a load, and therefore the steering unit 30 must be pressed against the steering post 20, and this further worsens the operation efficiency.
Furthermore, when that portion of the wire harness 60, projecting from the steering post 20, is pushed into the recess, this portion is deformed, and if this deformed portion is held between the steering unit 30 and the steering post 20, the steering unit 30 can not be fixed to the steering post 20, and therefore the operation must be again carried out from the beginning. Alternatively, if the steering unit 30 is forcibly fixed to the steering post 20, a sheath of the wire harness 60, held between the steering unit 30 and the steering post 20, is broken, which causes an insulation failure.
This invention has been made in order to solve the above problems of the conventional structure, and an object of the invention is to provide a steering unit-mounting structure in which connectors on a steering unit can be easily and positively connected respectively to connectors associated with a steering post, and besides the steering unit can be quite easily mounted on the steering post.
The above object has been achieved by a steering unit-mounting structure of the present invention wherein a steering unit, including at least a combination switch and a first connector connected to the combination switch, is mounted on a steering post simultaneously when the steering unit is connected to a second connector fixed to the steering post, comprising: when the steering unit is to be mounted on the steering post, the second connector is beforehand fixed in such a position that the second connector is opposed to the first connector on the steering unit, and is connectable to the first connector; and the steering unit is positioned and provisionally fixed relative to the steering post by connecting the first connector to the second connector.
In the above construction, the second connector may be slightly movable in upward, downward, right and left directions.
A pair of the first connectors, as well as a pair of the second connectors, may be arranged symmetrically with respect to a steering shaft extending through the steering post.
Lever-type connectors may be used as the first and second connectors, respectively, and one of the connectors has a rotary lever having an engagement portion, and a boss for engagement with the engagement portion of the rotary lever is formed on the other connector.
A male thread may be provided at the first connector, and a female thread for being threaded on the male thread may be provided at the second connector.
The present disclosure relates to the subject matter contained in Japanese patent application No. Hei. 10-346132 (filed on Dec. 4, 1998) which is expressly incorporated herein by reference in its entirely.